Doctors should give underage teenagers prescriptions for emergency contraceptives such as Plan B before they start having sex instead of waiting until a young patient's "plan A" goes awry, the American Academy of Pediatrics says in a new policy statement. It says doctors, including pediatricians, should also counsel teens on the options for emergency birth control as part of an overall strategy to reduce teen pregnancy.

The academy is issuing the new position paper, published online Monday by the journal Pediatrics, as physicians and other health experts struggle to reduce the nation's high birthrate among adolescents.

Teen pregnancies in the United States have declined over the last 20 years, but the incidence is still the highest in the developed world, according to data released this year by the Centers for Disease Control and Prevention.

The birthrate among Americans 15 to 19 dropped 44 percent between 1991 and 2010, to 34.3 births per 1,000 women, the CDC reported. But that's still about five times the teen birthrate in France and 2 1/2 times the rate in Canada, according to U.N. data. It also is higher than the rates in China and Russia.

Rates of sexual assault are highest among teens and young adults, according to the Justice Department's Office on Violence Against Women. And all in all, nearly 80 percent of teen pregnancies in the United States are unintended, occurring after unprotected sex or "underprotected" sex - when the contraceptive method of choice fails.

It's a pressing issue, Dr. Cora Breuner said, because babies born to teens have been shown to fare poorly compared with their peers. Among other problems, they are more likely to do worse in school and suffer behavior problems such as truancy and early sexual activity. Breuner, a physician at Seattle Children's Hospital, helped write the new policy statement.

Emergency contraceptives, such as levonorgestrel, if taken within three to five days, can prevent pregnancy by stopping the ovary from releasing an egg or by stopping sperm from fertilizing an egg. The drugs are also thought to change the uterine lining, thwarting a pregnancy that might otherwise take hold.

But emergency contraception pills are most effective when they're used within the first 24 hours after unprotected sex and teens are more likely to use them if they're readily available, Breuner said.

The drugs are sold under the brand names Plan B and Next Choice, and their possible side effects include nausea, vomiting, diarrhea and an untimely menstrual cycle.

Young women who are 17 or older can already get emergency contraceptives over the counter.